Method of folding and sealing sheet material



Dec. 9, 1947. I E.. A. PARDEE METHOD OF FOLDING AND SEALING SHEETMATERIAL Filed Jan. 21, 1944 [j INVENTOR. ZZzwarcz' di a/de I wePatented Dec. 9, 1947 7 METHOD OF FGLDING AND SEALING SHEET MATERIALEdward A. lardee, Mount Vernon, Ohio, assignor, by mesne assignments, toShellmar Products Corporation, Mount Vernon, Ohio, a corporation ofDelaware Application January 21, 1944, Serial No. 519,134

4 Claims.

The present invention relates to the fabrication of sheet material intoarticles such as liners for containers as well as protective covers forvarious other manufactures, such articles also being useful asreceptacles and containers for various packaging purposes.

A principal object of the invention is the provision of such an articleand method for its manufacture in which a tubular formation of sheetmaterial has portions removed from one end thereof so that the remainingportions can be converted into a liner, protective cover, or a containerwith a novel type of flat end closure.

More specifically, it is an object of the present-invention to providean article of the kind herein described which comprises side wallsforming a tubular body portion having triangular sections at the base ofthe side walls projecting inwardly of the body portion toward a commoncenter, each of the sections being sealed to an adjacent section alongmarginal edges to form a novel type of fiat bottom for such an article.

Another object of the invention is the provision of a novel flat bottomarticle which can be used as a liner for flat walled containers, or as aflat bottom bag.

A further object of the invention is the provision of a novel flatbottom article which can be used as a liner for cylindrical containers,or as a flat bottom bag with cylindrical side walls.

Yet another object of the invention is the provision of an article ofthe kind herein described which constitutes a square liner or bag havinga square fiat bottom which can be transformed to a round flat bottom,and the side Walls of which can be transformed from square tocylindrical shape in cross section.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

The invention accordingly comprises the several steps and the relationof one or more of such steps with respect to each of the others, and thearticle possessing features, properties, and the relation of elements,which are exemplifled in the following detailed disclosure, and thescope of the application of which will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawing, in which:

Fig. l is a plan view of a cut sheet of suitable material folded andsealed to produce one form of article embodying the present invention;

Fig. 2 is a plan view of the sheet shown in Fig. 1 folded and marginallysealed to itself along one edge;

Fig. 3 is a perspective view of the sealed sheet of Fig. 2 opened upinto tubular formation for purposes of illustration;

Fig. 4 is a plan view showing the tube of Fig. 3 again flattened as inFig. 2 and with the outside marginal portions of its triangularextensions sealed together;

Fig. 5 is a view similar to Fig. 4 in which the walls have been openedup and flattened in an opposite direction depicting the remainingoutside marginal portions of its triangular extensions sealed together;

Fig. 6 is a, perspective view of the sealed article of Fig. 5 ininverted position illustrating the novel type of flat bottom whichresults from such sealing operations;

Fig. 7 is a lower fragmentary portion of a sheet of material such asthat shown in Fig. 1, having reinforcing segments secured to thetriangular sections;

Fig. 8 is a transverse sectional view taken along the lines 88 of Fig.7;

Fig. 9 is a plan view of a sheet such as shown in Fig. 7 completelysealed as illustrated in Fig 6 showing the novel square bottom formationwith the segments secured thereto; 7

Fig. 10 is a plan view illustrating a modified form of reinforcing andforming element subsequently applied to a square bottom formation aftersealing;

Fig. 11 is a fragmentary portion in section taken along the lines ll|lof Fig. 10; and

Fig. 12 is a perspective view of a multi-walled tubular formationillustrating a further modification of the invention and the resultingnovel flat bottom obtained thereby.

Referring more particularly to Fig. l of the drawing, there isillustrated generally at 20 a single web of sheet material forfabricating articles of the type herein described. It should be notedthat while a single sheet of material is here shown, largely forpurposes of illustration, any number of single panels can be securedtogether, particularly where the ultimate article is of extensive area,to provide a single sheet such as that of Fig. 1. This sheet has beencut to provide triangular sections 2|, 22, 23 and 24. Preferably thesheet is provided with score lines 25, 26 and 21. Where single panelsare seamed together to produce such a sheet, the seams will take theplace of the score lines. In any event, the score lines, or the seams,define side wall 3 panels 28, 29, 3|] and 3|. Preferably, at least foursuch panels are used in making the bag in accordance with the principlesof the present invention, but it will be understood that this providesonly a square bag. In the event a larger number of panels are to beutilized, it will then be necessary to vary the degree of the angularsections which project from each panel. That is, when a square bag offour panels is desired, the angle at the apex of each triangular sectionwill have to be cut to 90 degrees. As a further illustration, suppose asheet having double the number of panels or eight walls is desired, eachangle of the triangular portion indicated will have to be cut at 45degrees. In other words, the size of the angle which must appear in thetriangular portions is equal to 360 degrees divided by the number ofpanels desired. It will also be observed, therefore, that as the numberof panels is increased and the size of each angle is correspondinglydecreased, an article which is cylindrical in cross section will beapproached.

Referring now to Fig. 2, it will be seen that panels 3| and 39 have beensuperimposed on panels 28 and 29 respectively. Thereafter the ends ofthe panels marginally are sealed together as indicated at 32. If athermoplastic material, such as pliofilm, is used, a coalesced or weldedseam will be obtained. However, any other type of material which "isheat sealing or which can be secured together by suitable adhesives canbe used. This includes fibrous materials, metallic foils, fabrics andthe like, depending upon the type of material it is desired to use insuch articles and the purposes for which they are intended.

After the seal 32 has been effected, the bag when opened up will form atube, as shown in Fig. 3. However, by restoring the tube to collapsedform, as indicated in Fig. 4, the same is ready for further sealing. Inthis position the collapsed tube is the same as that shown in Fig. 2.The outside marginal portions of the triangular sections where they arein face-to-face contact are next sealed together as indicated at 33 and34. It should here be noted that this order of steps is essential to themanufacture of this type of bag. It will be seen that sealing adjacentportions other than the outside marginal portions of the construction atthis point will make impossible the fabrication of such an article asherein contemplated.

The partially sealed tube of Fig. 4 is next opened up and the walls orpanels 3| and 28 brought against the panels 30 and 29 respectively toallow of the completion of the sealing of the bottom of the bag. Inother words, the marginal portions (1 and a of triangular sections 2|and 24 have been scaled together, as indicated at 34, and the marginalportions 12 and a of triangular sections 22 and 23 have been sealedtogether, as indicated at 34. With the opening and refolding of thepartially formed bag, so that the panels 3| and 28 come in contact oroverlie the panels 39 and 29, respectively, the sealing of the marginalportions 17 and b of triangular sections 22 and 23 will be permitted, aswell as the marginal portions 1) and b of the triangular sections 2| and24. The final seals are indicated at 35 and 36, respectively, in Fig. 5.

When the bag is completely opened up into squared position and viewedfrom the bottom, it will appear as illustrated in Fig. 6. A bag having,for example, six panels and, therefore, triangular sections of 60degrees at each apex, will appear as illustrated in Fig. 12.

A liner or bag of the type above described, which is square in crosssection and thus has a square bottom, can readily be transformed into around flat bottom bag in which the base becomes circular, and the wallsbecome cylindrical in cross section. This can be accomplished in severalways. For example, if at the time the triangular sections 2| to 24 areout, there are secured curved reinforcing segments 31, 38, 39 and 40into these triangular portions, as indicated in Fig. '7, a novel type offiat bottom bag can be provided. These segmental portions may be of anysuitable stiff material, such as fiber or cardboard, and may be pastedon the inside, on the outside, or on both sides in superimposedrelationship with respect to each other, with the bag materialtherebetween. After the liner has been fabricated as illustrated inFigs. 1 to 6, these segments 31 to 40 will form a disconnected circularelement in the flat bottom of the square bag. The reason for usingsegments initially in the fabrication of the article is to permit thesealing of the seams in the formation of the flat bottom and to avoidoverlapping of the seams if the reinforcing segments are placed on theseam side of the fiat bottom.

In the modification shown in Fig. 10 an unbroken circular element orring 4| has been secured to the flat bottom of the bag after the samehas been fabricated, as illustrated in Fig. 6. Preferably, if thecircular element 4| is placed on the outside, or whichever happens to bethe seam side, of the liner or bag it can be gouged out, as indicated at42 at points where the seams 33, 34, 35 and 35 are bridged thereby, asindicated in Fig. 11.

In addition to reinforcing the bottom of such a liner or bag, theprimary purpose of securing these circular elements thereto is to permitthe bag to be changed from a square type to a substantially circulartype in cross section with a circular fiat bottom base. For example,when such an article is used as a liner and is put into a barrel whichis to be filled with a granular material, substantially no overlappingof the bottom and side seams will occur. The square liner is merelyinserted into the bag to be filled. By pulling up the side of the bag,the bottom will conform to the circular grommet or ring, therebychanging the contour of the bag from square to circular at the bottom,as well as changing its contour around the vertical walls from flat tocurved. In this way a square bottom bag which is square in cross sectioncan readily be utilized in cylindrical containers. This solves a problemof long standing in the industry, in that square bags can now beutilized in large circular drums, Whether the material to be packaged ispowdered, granular, semi-solid or even liquid. .Also, hermetic seals canbe imparted to the seam structures Where the type of liner material usedis of a thermoplastic nature and which autogenously can be bondedtogether.

The article herein described can also be used for covering other largeand small articles of manufacture where it is desired to keep the samehermetically sealed, and to protect the same against moisture and vapor.For example, all types of articles, from precision instruments toturrets on tanks, arm tanks themselves, airplane engines, etc., whetherthey are of rectangular, square or round construction, can be coveredand sealed by covering the same with articles of this eneral type.

It will thus be seen that the objects hereinbefore set forth can readilyand efficiently be attained and since certain changes in carrying outthe above method and certain modifications in the article which embodythe invention can be made without departing from its scope, it isintended that all matter contained in the above description or shown inthe accompanying drawing shall be interpreted as illustrative and not ina limiting sense.

Having described my invention, what I claim as new and desire to secureby Letters Patent is:

1. The method of fabricating sheet material into an article of the kinddescribed, which comprises providing a web of said material withtriangular projections along one edge thereof, folding said Web uponitself and sealing the free ends thereof together marginally to form atubular body, sealing together adjacent outside marginal portions ofsaid triangular projections, r'e-forming and folding the tube to bringremaining unsealed marginal portions of said triangular projectionsadjacent each other and into outside position, and sealing said outsideportions to provide a flat bottom for said article.

2. The method of fabricating sheet material into an article of the kinddescribed, which comprises cutting a web of said material to providetriangular projections along one edge thereof, folding said web uponitself and sealing the free ends thereof together marginally where theyare in face-to-faoe contact to form a tubular body, sealing togetheradjacent outside marginal portions of said triangular projections inface-to-face relationship, re-forming and folding the tube to bringremaining unsealed marginal portions of said triangular projectionsadjacent each other and into outside position, and sealing said outsideportions to provide a flat bottom for said article.

3. A method of fabricating sheet material into an article of the kinddescribed, which comprises providing a web of said material withtriangular projections along one side thereof, securing to eachtriangular projection a curved segment of reinforcing material, foldingsaid web upon itself and sealing the ends thereof together marginally toform a tubular body, sealing together adjacent outside marginal portionsof said triangular projections, re-forming and folding the tube to bringremaining unsealed marginal portions of said triangular projectionsadjacent each other and into outside position, and sealing said outsideportions to provide a flat bottom for said article.

4. The method of fabricating sheet material into an article of the kinddescribed, which comprises cutting a web of said material and leavingtriangular projections along one edge thereof, folding said web uponitself and sealing the free ends thereof together marginally to form atubular body, sealing together adjacent outside marginal portions ofsaid triangular projections, reforming and folding the tube to bringremaining unsealed marginal portions of said triangular projectionsadjacent each other and into outside position, sealing said outsideportions to provide a flat bottom for said article, and securing acircular reinforcing element against the bottom of said article-todefine a circular base when the side walls of the tube are pulledagainst said circular element.

EDWARD A. PARDEE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,091,291 Ringler Aug. 31, 19372,336,763 Wilcox Dec. 14, 1943 1,397,756 Drysdale Nov. 22, 19211,853,191 Benke Apr. 12, 1932 2,263,545 waldvogel Nov. 18, 1941

